System and method for distributed call processing and audio reinforcement in conferencing environments

ABSTRACT

Systems, apparatus, and methods for processing audio signals associated with conferencing devices communicatively connected in a daisy-chain configuration using local connection ports included on each device are provided. One method involving a first conferencing device comprises receiving auxiliary mixed microphone signal(s) from at least one other conferencing device via at least one local connection port, each auxiliary signal comprising a mix of microphone signals captured by the at least one other conferencing device; determining a gain adjustment value for each auxiliary mixed microphone signal based on a daisy-chain position of the at least one other conferencing device relative to the position of the first conferencing device; adjusting a gain value for each auxiliary mixed microphone signal based on the corresponding gain adjustment value; generating a loudspeaker output signal from the gain-adjusted auxiliary mixed microphone signal(s); and providing the loudspeaker signal to the loudspeaker of the first conferencing device.

TECHNICAL FIELD

This application generally relates to conferencing environments. Inparticular, this application relates to audio reinforcement anddistributed call processing using daisy-chained units in a conferencingenvironment.

BACKGROUND

In conferencing environments, such as boardrooms, video conferencingsettings, and the like, one or more microphones are used to capturesound from multiple audio sources. The audio sources may include in-roomhuman speakers, and in some cases, loudspeakers for playing audioreceived from human speakers that are not in the room, for example. Thecaptured sound may be disseminated to an audience through loudspeakersin the environment, a telecast, a webcast, telephony, etc. The types ofmicrophones and their placement in a particular conferencing environmentmay depend on the locations of the audio sources, the loudspeakers,physical space requirements, aesthetics, room layout, and/or otherconsiderations. For example, in some environments, the microphones maybe placed on a table or lectern near the audio sources. In otherenvironments, the microphones may be mounted overhead to capture thesound from the entire room, for example.

Some conventional conferencing systems include a single conferencingdevice or other hardware unit comprising one or more microphone(s) forcapturing sound from near-end audio sources (e.g., human speakers) and aloudspeaker for playing sound received from far-end audio sources.In-room conference participants gather around the single conferencingdevice to speak into the microphone(s) and to hear far-end audio throughthe loudspeaker. In some larger conferencing spaces (e.g., a largeboardroom), two or more conferencing devices may be electricallyconnected to each other but placed at different locations in the room oron the table, to help capture near-end audio sources spread out aboutthe room and broadcast any far-end audio throughout the conferencingspace.

In the case of multiple conferencing devices, either a remote server orone of the conferencing devices is typically assigned as the primarydevice for processing all near-end audio signals for transmission to thefar-end, as well as being the source of all far-end audio signalsincluded in the conference. For example, the primary device may beconfigured to receive near-end audio, or microphone, signals from eachof the conferencing devices, mix the received signals together togenerate a single mixed microphone signal, and then send the mixedmicrophone signal back to each of the conferencing devices fortransmission to the far-end audio sources connected thereto. Likewise,the primary device may also receive audio signals from each far-endaudio source connected thereto, mix the received signals together togenerate a single far-end audio signal, and then send the mixed far-endsignal to each of the conferencing devices for playback via thecorresponding loudspeakers. Such centralized audio processing techniqueslimit the expandability of conferencing systems to cover more area andmore in-room and/or remote users. For example, many conventionalconferencing systems may require substantial re-configuring of itscomponents in order to add more conferencing devices and/or far-endaudio sources to the system.

Another drawback of conventional conferencing systems is that they donot facilitate audibility of local near-end audio for in-room listenersthat are located far away from, or on an opposite side of the room than,the speaker. Typically, only the far end audio signals are broadcast bythe loudspeaker of each conferencing device because broadcasting thenear-end audio through the loudspeakers may be perceived as too loud orirritating, especially for the in-room listeners that are close enoughto the speaker to hear the local audio first hand.

Accordingly, there is still a need for techniques that can address theseconcerns, for example, by enhancing near-end audio intelligibility forin-room participants and allowing for easy expandability, ordownscaling, as the spatial needs change for a conferencing environment.

SUMMARY

The invention is intended to solve the above-noted problems by providingsystems and methods that are designed to, among other things: (1)enhance audibility of all near-end audio, regardless of the listener'slocation within the conferencing space relative to the speaker, and (2)easily accommodate additional audio sources in an expanding conferencingspace.

One example embodiment comprises a method of processing a plurality ofaudio signals associated with a conferencing environment comprising aplurality of conferencing devices connected in a daisy-chainconfiguration, using a first one of the conferencing devices. The firstconferencing device comprises at least one microphone, at least oneloudspeaker, at least one processor, one or more external communicationports for connecting to one or more external communication devices, anda pair of local connection ports for communicatively connecting to atleast one other conferencing device. The method comprises receiving oneor more auxiliary mixed microphone signals from at least one of thelocal connection ports, each of the one or more auxiliary mixedmicrophone signals comprising a mix of microphone signals captured by arespective one of the other conferencing devices; determining, using atleast one processor, a gain adjustment value for each auxiliary mixedmicrophone signal based on a position of the other conferencing devicethat captured the signal, relative to a position of the firstconferencing device within the daisy-chain configuration; adjusting,using at least one processor, a gain value for each auxiliary mixedmicrophone signal based on the corresponding gain adjustment value;generating, using at least one processor, a loudspeaker output signalfrom the one or more gain-adjusted auxiliary mixed microphone signals;and providing the loudspeaker output signal to the at least oneloudspeaker of the first conferencing device

Another example embodiment comprises a conferencing device forcommunicatively coupling to one or more other conferencing devices in adaisy-chain configuration. The conferencing device comprises a pair oflocal connection ports configured for communicatively connecting to atleast one of the one or more other conferencing devices, at least one ofthe local connection ports being further configured to receive one ormore auxiliary mixed microphone signals from the one or more otherconferencing devices, wherein each auxiliary mixed microphone signalcomprises a mix of microphone signals captured by a respective one ofthe other conferencing devices. The conferencing device also comprisesone or more processors configured to: determine a gain adjustment valuefor each auxiliary mixed microphone signal based on a position of theother conferencing device that captured the signal, relative to aposition of the conferencing device within the daisy-chainconfiguration, adjust a gain value for each auxiliary mixed microphonesignal based on the corresponding gain adjustment value, and generate aloudspeaker signal from the one or more gain-adjusted auxiliary mixedmicrophone signals. The conferencing device further comprises at leastone loudspeaker for outputting the loudspeaker signal.

Another example embodiment includes a conferencing system comprising aplurality of conferencing devices arranged in a daisy-chainconfiguration, each conferencing device comprising: a pair of localconnection ports configured for communicatively connecting to at leastone other conferencing device, one or more external communication portsconfigured to connect to one or more external communication devices, atleast one microphone configured to provide one or more local microphonesignals, at least one loudspeaker for outputting a loudspeaker signal,and one or more processors for processing received audio signals andproviding the processed audio signals to one or more components of theconferencing device. The system further comprises one or moreinterconnects configured for coupling to the local connection ports ofthe plurality of conferencing devices. Each of the conferencing devicesreceives one or more auxiliary mixed microphone signals at one or moreof the local connection ports and provides a local mixed microphonesignal to at least one of the local connection ports, the local mixedmicrophone signal comprising a mix of microphone signals captured by itsown microphones, and each auxiliary mixed microphone signal comprising amix of microphone signals captured by the microphones of a respectiveone of the other conferencing devices. Moreover, the one or moreprocessors of each conferencing device is configured to: determine again adjustment value for each auxiliary mixed microphone signal basedon a position of the other conferencing device that captured the signal,relative to a position of the conferencing device within the daisy-chainconfiguration, adjust a gain value for each auxiliary mixed microphonesignal based on the corresponding gain adjustment value, and generatethe loudspeaker signal from the one or more gain-adjusted auxiliarymixed microphone signals.

These and other embodiments, and various permutations and aspects, willbecome apparent and be more fully understood from the following detaileddescription and accompanying drawings, which set forth illustrativeembodiments that are indicative of the various ways in which theprinciples of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an exemplary conferencingenvironment including multiple near-end audio sources, multiple far-endaudio sources, and a number of spatially-distributed conferencingdevices, in accordance with some embodiments.

FIG. 2 is a block diagram of various components of an exemplaryconferencing device, in accordance with some embodiments.

FIG. 3 is a schematic representation of exemplary output signalsproduced by conferencing devices in an exemplary conferencing system, inaccordance with some embodiments.

FIG. 4 is a functional block diagram of an exemplary conferencingdevice, in accordance with some embodiments.

FIGS. 5 and 6 are flowcharts illustrating exemplary operations forprocessing audio signals in a conferencing device, in accordance withsome embodiments.

DETAILED DESCRIPTION

The description that follows describes, illustrates and exemplifies oneor more particular embodiments of the invention in accordance with itsprinciples. This description is not provided to limit the invention tothe embodiments described herein, but rather to explain and teach theprinciples of the invention in such a way to enable one of ordinaryskill in the art to understand these principles and, with thatunderstanding, be able to apply them to practice not only theembodiments described herein, but also other embodiments that may cometo mind in accordance with these principles. The scope of the inventionis intended to cover all such embodiments that may fall within the scopeof the appended claims, either literally or under the doctrine ofequivalents.

It should be noted that in the description and drawings, like orsubstantially similar elements may be labeled with the same referencenumerals. However, sometimes these elements may be labeled withdiffering numbers, such as, for example, in cases where such labelingfacilitates a more clear description. Additionally, the drawings setforth herein are not necessarily drawn to scale, and in some instancesproportions may have been exaggerated to more clearly depict certainfeatures. Such labeling and drawing practices do not necessarilyimplicate an underlying substantive purpose. As stated above, thespecification is intended to be taken as a whole and interpreted inaccordance with the principles of the invention as taught herein andunderstood to one of ordinary skill in the art.

It should also be noted that connections between the components shown inFIGS. 1-4 are intended to depict the potential flow of control signals,audio signals, and/or other signals over wired and/or wirelesscommunication links. Such signals may be in digital and/or analogformats.

Systems, devices, and methods are provided herein for a conferencingsolution that utilizes, among others, daisy-chaining, matrix mixing, andvoice lifting techniques to provide a unified call experience acrossmultiple audio sources, distributed audio processing across allconferencing devices, enable a given conferencing system to easilyexpand as needed (e.g., to cover larger areas and/or more callparticipants), and provide enhanced intelligibility of near-end audio,particularly in large conferencing spaces. In embodiments, theconferencing solution described herein utilizes a digital audio bus toconnect multiple conferencing devices to each other in a daisy-chainconfiguration and efficiently distribute call processing loads acrossthe multiple conferencing devices. The daisy-chained devices transmitaudio signals between themselves, and also communicate with externaldevices associated with the remote participants, so that each callparticipant, whether present in the conferencing space or locatedremotely, can listen to all other participants to the conference callwithout hearing an echo or experiencing feedback. In addition, theconferencing solution alleviates the acoustical challenges of a largeconferencing space by leveraging the position of each conferencingdevice within the daisy-chain configuration to enhance only the in-roomsounds (e.g., voices) that need reinforcement.

More specifically, FIG. 1 illustrates an exemplary conferencingenvironment 100 in which a plurality of conferencing devices 102 areused to facilitate a conference call (e.g., teleconference, videoconference, web conference, etc.) involving a plurality of in-room ornear-end participants 104 (e.g., human speakers) and one or more remoteor far-end participants (not shown) communicatively connected to theenvironment 100 through a plurality of external communication devices106. The environment 100 may be, for example, a conference room,boardroom, meeting room, or any other type of conferencing space, andthe conferencing devices 102 may be spatially distributed or dispersedaround the conferencing space to capture speech or other sounds from amaximum number of the near-end participants 104. In the illustratedexample, the near-end participants 104 are seated at chairs around oneor more conference tables 108, and the conferencing devices 102 areplaced at various locations on the tables 108 adjacent to one or more ofthe participants 104.

The external communication devices 106 may also be placed on the tables108 or otherwise near the conferencing device 102 to which they arecommunicatively coupled, as shown in FIG. 1. The far-end participants tothe conference call are considered “remote” because they are not presentwithin the same room or conferencing space as the other, “in-room”participants 104 and are connected to the environment 100 only throughthe external communication devices 106. As an example, the remoteparticipants may be nearby, such as, e.g., in another room within thesame building, or far away from the conferencing space, such as, e.g.,in another city, state, or country.

Other configurations and placements for the conferencing devices 102,in-room participants 104, external communication devices 106, tables108, etc. are also contemplated and possible. For example, the in-roomparticipants 104, or other near-end audio sources, may be standing orwalking around the environment 100, instead of being seated at setpositions. As another example, in some cases, the conferencing devices102 may be placed on, or attached to, other surfaces in the conferencingenvironment, such as, e.g., a lectern, desk, wall, ceiling, etc.

According to embodiments, each conferencing device 102 includes one ormore microphones for capturing near-end audio, such as, e.g., speechspoken by the near-end participants 104 present in the conferencingspace, and at least one loudspeaker for disseminating, to the near-endparticipants 104, far-end audio received from the external communicationdevices 106, such as, e.g., speech or other sounds produced by theremote participants present at the other end of the conference call. Theloudspeaker of each conferencing device 102 also outputs a gain-adjustedmix of near-end audio signals received from other conferencing devices102, so that the sounds generated by near-end participants locatedfurther away from the conferencing device 102 can be heard more clearlyor intelligibly by the near-end participants located adjacent to thatdevice 102, as described in more detail herein.

To facilitate these and other functionalities, each conferencing device102 may be coupled to at least one other conferencing device 102 inseries, so as to form a daisy-chain configuration for sharing bothnear-end and far-end audio signals with each other, as shown in FIG. 1.In embodiments, each conferencing device includes a pair of localconnection ports for connecting to one or more other conferencingdevices using one or more cables 110 (also referred to herein as“interconnects”). For example, each conferencing device 102 may receivenear-end audio signals from another conferencing device 102 that ispositioned “upstream,” or is connected to an input communication port ofthe receiving device 102 by one of the cables 110. In addition, eachconferencing device 102 may transmit a mix of its own near-end audiosignals (e.g., the audio signals captured by its own microphones) andthe near-end audio signals received at its input port to yet anotherconferencing device 102 that is positioned “downstream,” or is connectedto an output communication port of the transmitting device 102 usinganother of the cables 110. Far-end audio signals received from thevarious external communication devices 106 may also be shared betweenthe conferencing devices 102 in a similar manner, as described in moredetail herein.

Upon receiving near-end and far-end audio signals, each conferencingdevice 102 may produce and output a loudspeaker signal that includes amix of all far-end audio signals received from the various externalcommunication devices 106, including those connected to otherconferencing devices 102 within the daisy-chain configuration, and again-adjusted version of the near-end audio signals received from theother conferencing devices 102. In addition, each conferencing device102 may provide, to each external communication device 106 connectedthereto, an audio mix comprised of all near-end audio signals capturedby the plurality of conferencing devices 102 within the daisy-chainconfiguration, as well as any far-end audio signals received from theother conferencing devices 102 and/or from the other externalcommunication devices 106 connected to the same conferencing device 102,as described in more detail herein. The external communication devices106 may transmit this audio mix to the remote participants that arepresent at the other end (e.g., far end) of the conference call, orconnected to the call via the one or more far-end devices.

As shown in FIG. 1, each external communication device 106 may beconnected to a respective one of the conferencing devices 102 througheither a wired connection (e.g., telephone cable, Ethernet cable, audiocable, data cable (e.g., USB), etc.) or a wireless connection (e.g.,Bluetooth®, WiFi, cellular, satellite, or other wireless networkconnection). Exemplary external communication devices 106 include,laptops or other personal computers; tablets, cellular phones, or othermobile devices; fixed or “landline” telephones; or any othercommunication device capable of transmitting audio signals between theremote participants and the in-room participants of the conferencingenvironment 100. As will be appreciated, in some cases, there may be noremote participants and therefore, no external communication devices 106within the environment 100. Though not shown, in some cases, a givenconferencing device 102 may be coupled to more than one externalcommunication device 106. Other combinations or configurations for thedevices 102 and 106 are also contemplated.

Referring additionally to FIG. 2, shown is a block diagram of anexemplary conferencing device 200 that may be included in theconferencing environment 100, for example, as one of the conferencingdevices 102 shown in FIG. 1. The conferencing device 200 may be a bridgedevice, speakerphone, USB speaker device, or other similar electronicdevice for enable communications between participants located near(e.g., in room) and far (e.g., remote). As shown, the conferencingdevice 200 may comprise various components including, for example, oneor more microphones 202, one or more loudspeakers 204, a communicationinterface 206, one or more processors 208, and a memory 210, allcommunicatively coupled by a local interface 212, such as a system bus,network, or other connection mechanism. In embodiments, the conferencingdevice 200 may use the communication interface 206 to establish wired orwireless communication with one or more external communication devices(e.g., external communication devices 106 of FIG. 1), each of which maybe communicatively connecting to one or more remote or far-endparticipants via an external network (e.g., voice over IP (VOIP),telephone network, local area network, Bluetooth, Internet, etc.). Theconferencing device 200 may further include a digital audio bus 214 forlocally connecting the conference device 200 to other conferencingdevices within the environment 100 (e.g., conferencing devices 102), asdescribed in more detail herein.

The one or more microphones 202 may detect and capture sound from thein-room or near end audio sources of the conferencing environment 100(e.g., in-room participants 104) and convert the sound to an analog (ordigital) audio signal. The microphone(s) 202 may be included in theconferencing device 200, as shown, and/or may be connected to theconferencing device 200 via a wired connection (e.g., Ethernet cable,USB cable, etc.) or a wireless connection (e.g., Bluetooth®, WiFi,etc.). The microphone(s) 202 may be configurable to form multiple polarpatterns and/or corresponding steering angles in order to optimallydetect and capture sound from the in-room audio sources. The polarpatterns that can be formed by the microphone(s) 202 may includeomnidirectional, cardioid, subcardioid, supercardioid, hypercardioid,bidirectional, and/or toroidal. In some cases, each microphone 202comprises multiple unidirectional microphone cartridges. For example,the unidirectional microphone cartridges may each be an electretcondenser microphone cartridge with a cardioid polar pattern and a rearport. In other cases, the microphone cartridges may have other polarpatterns and/or may be dynamic microphones, ribbon microphones,piezoelectric microphones, MEMS microphones, and/or other types ofmicrophones. In some embodiments, the desired polar patterns and/ordesired steering angles formed by the microphone(s) 202 can beconfigured by a user through software. In such cases, an electronicdevice may be in communication with the conferencing device 200 tocontrol such parameters. The electronic device may include, for example,a smartphone, tablet computer, laptop computer, desktop computer, etc.In some embodiments, the conferencing device 200 may include controls toadjust parameters of the microphones, such as polar pattern, gain, noisesuppression, muting, frequency response, etc.

The one or more processors 208 may be configured, e.g., using softwarestored in the memory 210, to process the analog audio signals generatedby the microphone(s) 202 and ultimately generate one or more digitalaudio output signals. In one embodiment, the processor(s) 208 mayinclude two or more separate processors, for example, at least one forconsolidating and formatting the individual audio signals (e.g., audioprocessor) and at least one for implementing digital signal processing(DSP) functionality (e.g., DSP processor). The conferencing device 200may also include other components (not shown), such as one or moreanalog to digital converters, codecs, encryption chips, audio mixers,etc., for processing and/or converting the analog audio signals todigital form (e.g., microphone signals, telephone signals, etc.). Thedigital audio output signals may conform to the Dante standard fortransmitting audio over Ethernet, in some embodiments, or may conform toanother standard. One or more polar patterns may also be formed by theone or more processors 208 from the audio signals generated by themicrophone(s) 202, and the processor(s) 208 may generate a digital audiooutput signal corresponding to each of the polar patterns. In otherembodiments, the microphone(s) 202 may output analog audio signals sothat other components and devices (e.g., processors, mixers, recorders,amplifiers, etc.) external to the conferencing device 200 can processthe analog audio signals captured by the microphone(s) 202.

The loudspeaker 204 may comprise one or more speakers or audioreproduction devices for playing out loud audio signals received fromfar-end audio sources via the communication interface 206 and/or otheraudio signals received from the processor(s) 208 via the local interface212. The far-end audio sources may be, for example, the externalcommunication devices 106 shown in FIG. 1, or any other deviceconfigured to provide speech or other sounds produced by human speakersthat are not physically present in the conferencing environment 100(e.g., the remote or far-end participants). The loudspeaker 204 may alsoreceive, from the processor(s) 208 via the local interface 212, one ormore near-end audio signals received from other conferencing devices 102within the conferencing environment 100. In some cases, the near-endaudio signals output by the loudspeaker 204 are the original analogaudio signals captured by the microphone(s) of the other conferencingdevices 102. In other cases, the near-end audio signals are the digitalaudio output signals converted back to analog audio signals so they canbe heard over the loudspeaker 204. According to embodiments, theloudspeaker 204 may be included in the conferencing device 200, asshown, and/or may be connected to the conferencing device 200 via awired connection (e.g., Ethernet cable, USB cable, etc.) or a wirelessconnection (e.g., Bluetooth®, WiFi, etc.).

The communications interface 206 comprises one or more externalcommunication ports, such as, e.g., a transceiver, data port (e.g.,input/output data port), parallel data port, serial data port, audioport (e.g., audio input/output port), or other communications device, tofacilitate communications between the conferencing device 200 and one ormore other devices, systems, or networks according to one or moreprotocols, including, for example, the external communication devices106 shown in FIG. 1. As shown in FIG. 2, the communications interface206 may include one or more wired communications interfaces, such as,e.g., a Universal Serial Bus (USB) port 216 (e.g., a USB-C port, astandard USB port, a mini-USB port, a micro-USB port, etc.), an audioinput/output port 218 (e.g., a 3.5 mm audio port, a telephone jack,etc.), an Ethernet jack or other network interface (not shown), ahigh-definition serial-digital-interface (HD-SDI) (not shown), etc. Asalso shown, the external communication ports of the communicationsinterface 206 may also include a wireless communication module 220. Thewireless communication module 220 may include receivers, transmitters,transceivers, ports, modems, and/or other communication devices forfacilitating wireless network communications according to certainprotocols. For example, the wireless communication module 220 mayinclude a Bluetooth® transceiver 222, a cellular transceiver (notshown), a wide area network transceiver (e.g., WiFi, WLAN, WWAN, etc.)(not shown), or the like.

The local interface 212 may include a data bus comprising one or morewires, traces, or other connection mechanisms for communicativelycoupling the one or more processors 208, memory 210, communicationinterface 206, loudspeaker 204, one or more microphones 202, and/or anyother applicable component of the conferencing device 200.

The digital audio bus 214 may be coupled to first and second localconnection ports 224 and 226, as well as the one or more processors 208and may be configured to facilitate communication between the ports 224,226 and the processor(s) 208. For example, the digital audio bus 214 mayreceive incoming signals from one or more of the ports 224, 226 andprovide the incoming signals to the processor(s) 208. The incomingsignals may have been transmitted to the conferencing device 200 by oneor more other conferencing devices. In addition, the digital audio bus214 may receive outgoing signals from the processor(s) 208 and providethe outgoing signals to one or more of the ports 224 and 226 fortransmission to one or more other conferencing devices. In someembodiments, the digital audio bus 214 may include a processor (e.g.,microprocessor) and a memory (e.g., electronic memory) to facilitate thesignal flow there through and perform other operations, as describedherein.

The digital audio bus 214 may also be configured to connect theconferencing device 200 in series with one or more other conferencingdevices to form a daisy-chained configuration (e.g., as shown byconferencing devices 102 in FIG. 1). For example, the digital audio bus214 may have one outlet or connection interface coupled to the firstlocal connection port 224 and another outlet coupled to the second localconnection port 226. Each bus outlet may have a specific designation(such as, e.g., “IN” or “OUT”), such that the outlets, and therefore,the local connection ports 224 and 226 coupled thereto, are notinterchangeable. In embodiments, a daisy-chain is formed by connectingthe second local connection port 226 (e.g., “OUT”) of each conferencingdevice to the first connection port 224 (e.g., “IN”) of anotherconferencing device until all of the conferencing devices within theconferencing space have been connected to at least one otherconferencing device. Other techniques for creating a daisy-chainconfiguration are also contemplated.

As shown in FIG. 1, once these connections are made, the conferencingdevices 102 located at the beginning (e.g., device A) and end (e.g.,device E) of the daisy chain may be physically connected to only oneother conferencing device 102, while each of the remaining, intermediateconferencing devices 102 (e.g., devices B, C, D) may be physicallyconnected to two other conferencing devices 102 (e.g., the immediatelypreceding device and the immediate succeeding device). Morespecifically, the end device E may have a connection at its firstconnection port 224 (to device D) but not at its second connection port226, and the beginning device A may have a connection at its secondconnection port 226 (to device B) but not at its first connection port224.

The flow of audio signals, and/or other signals, between theconferencing devices 102 within the daisy-chain configuration may bedetermined by the manner and/or order in which the devices 102 areconnected. For example, in some cases, signals and/or information mayflow forward or front to end, e.g., from device A to device B, to deviceC, and so on, until reaching device E. In other cases, for example, thesignal flow may be reversed, so that device E provides audio signals todevice D, and so on until the signals reach device A at the beginning ofthe daisy chain. In some embodiments, a bidirectional signal flow may bepreferred, so that the audio signals produced by or received at eachconferencing device 200 can be shared with each other conferencingdevice.

In some embodiments, the digital audio bus 214 is able to determine aposition of the conferencing device 200 within the daisy-chainconfiguration upon identifying the connections, or lack thereof, toother conferencing devices 102 at the local connection ports 224 and226. For example, if the second connection port 226 of the conferencingdevice 200 is connected to another conferencing device 102, but thefirst connection port 224 of said device 200 is free or unconnected,then the conferencing device 200 may be deemed to be in a first orbeginning position of the daisy-chain configuration. As another example,if the first connection port 224 of the conferencing device 200 isconnected to another conferencing device 102, but the second connectionport 226 of said device 200 is free or unconnected, then theconferencing device 200 may be deemed to be in a last or end position ofthe daisy-chain configuration.

Once one of the conferencing devices 102 identifies itself as being inthe first daisy-chain position, an automatic serial self-discoveryprocess may continue by enumerating, or sequentially assigning,positions to the remaining conferencing devices (e.g., second, third,fourth, etc.) based on the serial connections between the devices. Forexample, referring again to FIG. 1, the digital audio bus 214 of deviceA may send a signal to the digital audio bus 214 of device B indicatingthat device A is in the first position. Upon learning that its firstconnection port 224 is connected to the conferencing device in the firstposition, the digital audio bus 214 of device B may automaticallydetermine its daisy chain position as being the second position and maysend a signal to the digital audio bus 214 of device C indicating thesame. This self-discovery process may continue until the lastconferencing device (e.g., device E) is assigned a position with thedaisy chain and/or is identified as being the end of the daisy-chain.

In embodiments, the self-discovery process may be automaticallyperformed every time the conferencing devices 102 are powered on orrestarted, without requiring user intervention. In some embodiments, theself-discovery process may also be dynamically performed, for example,every time the daisy-chain configuration is changed by moving, adding,or removing one of the conferencing devices, without requiring userintervention. In such cases, once the daisy-chain is reconfigured, apower cycle may be initiated (e.g., by turning each of the conferencingdevices 102 off and on), which may automatically launch a newself-discovery cycle.

Each of the conferencing devices 102 may be assigned a unique identifieror node name that is used to identify the conferencing device 102 to theother devices 102 within the conferencing environment 100. In somecases, each device's self-assigned daisy-chain position, whethernumerical (e.g., 1, 2, 3, etc.) or textual (e.g., A, B, C, etc.), mayalso serve as the unique identifier for that device 102. In other cases,each daisy-chain position may be associated with a separate node name,or other identifying information, and said node name or identifier maybe assigned to the conferencing device 102 located at the correspondingposition.

In some embodiments, the digital audio bus 214 of the conferencingdevice 200 may be configured to provide or create a multichannel,time-division multiplexed link with each of the other conferencingdevices connected thereto (or more specifically, the digital audio busesincluded therein). For example, the digital audio bus 214 may be a highbandwidth digital bus capable of transporting bidirectional synchronousdata, such as, e.g., digital audio data, together with control data,clock, and, in some cases, power, over a single cable, such as, e.g., aCAT-5 cable, Ethernet cable, or other 2-wire, twisted pair cable (e.g.,cable 110 in FIG. 1). The digital audio bus 214 may be configured tosupport a direct point-to-point connection between the conferencingdevice 200 and each other conferencing device coupled thereto, and thisinterconnection may allow multiple, daisy-chained conferencing devices(e.g., devices 102) at different locations to contribute to or consumethe time-division-multiplexed channel content being transported betweensaid devices via their digital audio buses. In addition, thebidirectional feature of the multi-channel link may allow each digitalaudio bus 214 to accept both upstream and downstream signal flows, orhave two separate channels for handling the same, which may allow forsimultaneous sharing of information across all devices 102 in thedaisy-chain. In some cases, the digital audio bus 214 may be configuredto use time-slots to facilitate the bidirectional signal flow and enablesimultaneous access to all information loaded onto the digital audio bus214.

In some embodiments, the digital audio buses 214 of the daisy-chainedconferencing devices 102 may be connected to each other in a linetopology (also known as “linear bus topology”), which may be “created”only after two or more devices 102 are coupled to each other. In suchcases, each of the conferencing devices 102 may be configurable aseither a master or slave device for this network topology. In oneexample embodiment, the digital audio bus 214 of the conferencing device102 that is identified as being in the first position of the daisy-chainconfiguration (e.g., device A in FIG. 1) may be assigned as the masterdevice, and all other conferencing devices 102 within the daisy-chainmay be assigned as slave devices. In another example embodiment, any oneof the digital audio buses 214 on the line topology may be assigned asthe master device, and may always remain the master device despite itsposition in the daisy-chain configuration. In such cases, the remainingdigital audio buses 214 may be assigned as slave devices regardless oftheir final position in the daisy-chain configuration.

In general, configuring the network of conferencing devices 102 to havea line topology can increase overall system integrity, robustness, andefficiency. For example, if one connection (e.g., one of the devices 102or interconnects 110) within the daisy-chain configuration iscompromised, only the conferencing devices 102 situated downstream fromthe faulty connection may be impacted, while the upstream devices 102may continue to operate as before. Also, after the initial set-up ofmaster-slave assignments, the digital audio bus 214 of each conferencingdevice 102 may not require further processor intervention to managenormal bus operation. Moreover, the line topology network allows theconferencing devices 102 to be quickly and easily added to, removedfrom, or moved around within the daisy chain. In other embodiments, theconferencing devices 102 may be connected using other networktopologies, such as, e.g., a ring topology, a star topology, a meshtopology, a hybrid topology, etc.

The local communication ports 224 and 226 may be any type of port orinterface configured to receive, or be coupled to, an interconnect orcable (such as, e.g., the cables 110 shown in FIG. 1) for operativelyconnecting the conferencing device 200 to other conferencing devices(e.g., conferencing devices 102). As an example, the local communicationports 224 and 226 may be configured to receive a CAT-5 cable, Ethernet,or other 2-wire, twisted pair cable. In some embodiments, the localconnection ports 224 and 226 may form part of the digital audio bus 214.For example, the ports 224 and 226 may be included on or otherwisecoupled to a transceiver chip that embodies the digital audio bus 214.In other embodiments, the local connection ports 224 and 226 may formpart of the conferencing device 200. In such cases, the ports 224 and226 may be physically separated from the digital audio bus 214 but maybe communicatively coupled to the digital audio bus 214 during assemblyor manufacture of the conferencing device 200.

In embodiments, the one or more processors 208 may include a generalpurpose processor (e.g., a microprocessor) and/or a special purposeprocessor (e.g., a digital signal processor (DSP)). The processor(s) 208may be any suitable processing device or set of processing devices suchas, but not limited to, a microprocessor, a microcontroller-basedplatform, an integrated circuit, one or more field programmable gatearrays (FPGAs), and/or one or more application-specific integratedcircuits (ASICs).

Memory 210 may be volatile memory (e.g., RAM including non-volatile RAM,magnetic RAM, ferroelectric RAM, etc.), non-volatile memory (e.g., diskmemory, FLASH memory, EPROMs, EEPROMs, memristor-based non-volatilesolid-state memory, etc.), unalterable memory (e.g., EPROMs), read-onlymemory, and/or high-capacity storage devices (e.g., hard drives, solidstate drives, etc.). In some examples, memory 210 includes multiplekinds of memory, particularly volatile memory and non-volatile memory.The memory 210 may be computer readable media on which one or more setsof instructions, such as software for operating the methods of thepresent disclosure, can be embedded. The instructions may embody methods500 and 600 shown in FIGS. 5 and 6, or any other methods or logicdescribed herein. The instructions may reside completely, or at leastpartially, within any one or more of the memory 210, the computerreadable medium, and/or within the processor 208 during execution of theinstructions.

The terms “non-transitory computer-readable medium” and“computer-readable medium” include a single medium or multiple media,such as a centralized or distributed database, and/or associated cachesand servers that store one or more sets of instructions. Further, theterms “non-transitory computer-readable medium” and “computer-readablemedium” include any tangible medium that is capable of storing, encodingor carrying a set of instructions for execution by a processor or thatcause a system to perform any one or more of the methods or operationsdisclosed herein. As used herein, the term “computer readable medium” isexpressly defined to include any type of computer readable storagedevice and/or storage disk and to exclude propagating signals.

It should be understood that examples disclosed herein may refer toconferencing devices having components that may or may not be physicallylocated in proximity to each other. Certain embodiments may take theform of cloud based systems or devices, and for those embodiments, theterm “conferencing device” should be understood to include distributedsystems and devices (such as those based on the cloud), as well assoftware, firmware, and other components configured to carry out one ormore of the functions described herein. Further, as noted above, one ormore features of the conferencing device 200 may be physically remote(e.g., a standalone microphone) and may be communicatively coupled tothe conferencing device 200, via an appropriate communication interface,for example.

FIG. 3 is a schematic representation of exemplary output signalsproduced by conferencing devices 302 in an exemplary conferencing system300 during a conference call, video conference, meeting, webinar, or thelike, in accordance with embodiments. The conferencing system 300 may beset up in a room or space similar to the conferencing environment 100shown in FIG. 1. The conferencing devices 302 may be arranged in adaisy-chain configuration using the techniques described herein and maybe configured to pick up near-end audio and disseminate far-end audiothroughout the conferencing space, similar to the arrangement shown inFIG. 1. While FIG. 3 shows three conferencing devices 302 in theconferencing system 300, it should be understood that more (or fewer)devices 302 may be included in other embodiments.

In some embodiments, each of the conferencing devices 302 shown in FIG.3 may be similar to the conferencing device 200 shown in FIG. 2. Forexample, each conferencing device 302 may include one or moremicrophones (such as, e.g., microphone(s) 202 shown in FIG. 2) forpicking up or capturing speech or other sounds produced by near-endaudio sources (e.g., in-room participants 104 shown in FIG. 1). Asshown, each of the conferencing devices 302 may also include aloudspeaker 304 (such as, e.g., loudspeaker 204 of FIG. 2) foroutputting audio signals (e.g., LS_(n) to near-end or in-roomparticipants seated near the conferencing device 302, or otherwisewithin audible range of the same. The conferencing devices 302 mayfurther include a communication interface 306 (such as, e.g.,communication interface 206 shown in FIG. 2) for outputting audiosignals (e.g., FE_(n)) to, and/or receiving audio signals from (e.g.,EXT_(n)), one or more external communication devices coupled to theconferencing device 302 (such as, e.g., external communication devices106 shown in FIG. 1). In embodiments, each conferencing device 302 mayalso be configured to operate internally according to the functionalblock diagram of FIG. 4, as described in more detail herein.

The external or far-end audio signals received via the communicationinterface 306 may represent speech or other sounds generated by far-endor remote participants to the conference call or meeting. As an example,each external communication device may be communicatively coupled, via awired or wireless connection, to one or more remote devices (e.g.,telephone, cell phone, tablet, laptop, desktop computer, etc.) beingused by one or more far-end participants to connect to and participatein the meeting. In embodiments, the communication interface 306 mayinclude one or more external communication ports (such as, e.g.,wireless transceiver 222, audio input/output port 218, and USB port 216of FIG. 2) capable of connecting to the one or more externalcommunication devices (e.g., laptop, cellphone, telephone, tablet, orthe like) using a wired or wireless connection. Thus, the external audiosignals may be generated by a remote device and transmitted to theexternal communication device that is communicatively coupled thereto,and the external communication device may provide the received externalaudio signal to the conferencing device 302 through the communicationsinterface 306.

In embodiments, the conferencing system 300 may be configured to outputto each far-end device, via the communication interface 306 and theexternal communication device connected thereto, all near-end audio(e.g., MIC_(n−1), MIC_(n), MIC_(n+1), etc.) and all far-end audioassociated with the conference call, except for the far-end audiosignals received from that far-end device (e.g., EXT_(n−1), EXT_(n*),EXT_(n+1)). In addition, the conferencing system 300 may be configuredto output to each near-end participant, via the loudspeaker 304 of thenearest conferencing device 302, all far-end audio received from theexternal communication devices connected to the conference call (e.g.,EXT_(n−1), EXT_(n), EXT_(n+1), etc.), as well as the near-end audiocaptured by the microphones of the other conferencing devices 302 withinthe room (e.g., MIC_(n−1), MIC_(n+1), etc.). As a result, eachparticipant to the conference call or meeting may hear the contributionsof each other participant to the meeting, regardless of whether theparticipants are at the near-end or far-end of the call.

In exemplary embodiments, dissemination of audio signals in this mannermay be achieved by leveraging the daisy-chain configuration of theconferencing system 300 to transmit audio signals from one conferencingdevice 302 to the next conferencing device 302, until all audio signalshave been received by all devices 302. For example, like theconferencing devices 102 shown in FIG. 1, the conferencing devices 302may be connected in series by using cables (e.g., cables 110 shown inFIG. 1) to couple one or more local connection ports (such as, e.g., thelocal connection ports 224 and 226 of FIG. 2) of each conferencingdevice 302 to one or more local connection ports of at least one otherconferencing device 302. In such cases, the direction of signal flowbetween the conferencing devices 302, and the content of said signals,may be determined by the order and manner in which the devices 302 areconnected to each other.

In some embodiments, the connections between the conferencing devices302 may be leveraged to form a digital audio bus (such as, e.g., thedigital audio bus 214 of FIG. 2) across the connected devices 302. Audiosignals, and/or other information, may be exchanged between theconferencing devices 302 via the cables connected there between and overone or more audio and/or data channels of the digital audio bus. Forexample, the digital audio bus may be configured to create amultichannel, time-division-multiplexed (TDM) link between and acrossthe conferencing devices 302 that is capable of handling upstream anddownstream signal traffic simultaneously. In such cases, each of theconferencing devices 302 may be assigned one or more TDM slots withinthe multi-channel link for sharing content produced by or received atthat device 302, and the other conferencing devices 302 may be able tosimultaneously access the shared content through the digital audio bus.As will be appreciated, other techniques may be used to share contentbetween the plurality of daisy-chained conferencing devices 302.

As shown in FIG. 3, the conferencing device 302 that is in a firstposition of the daisy-chain configuration (e.g., device A) may have afirst connection port (e.g., first port 224 of FIG. 2) that isunconnected or open, while a second connection port (e.g., second port226 of FIG. 2) is connected to the conferencing device 302 that is in asecond daisy-chain position (e.g., device B). Likewise, the conferencingdevice 302 that is in an end position of the daisy-chain configuration(e.g., device C) may have its first connection port coupled to theconferencing device 302 that is in the immediately preceding position(e.g., device B), while the second connection port of the end device mayremain unconnected or open. Further, each of the intermediate deviceswithin the daisy-chain configuration (e.g., device B) may have its firstconnection port connected to the conferencing device 302 that is in theimmediately preceding position (e.g., device A) and may have its secondconnection port connected to the conferencing device 302 that is in theimmediately succeeding position (e.g., device C).

In some embodiments, audio and/or other signals may flow sequentiallythrough the daisy-chain configuration from the first of the conferencingdevices 302 to the last of the conferencing devices 302, for example,using a downstream channel. In some embodiments, signals may also flowin the reverse direction, from the last of the conferencing devices 302to the first of the conferencing devices 302, for example, using anupstream channel. The content of the signals output by each conferencingdevice 302 may include a local audio output signal (e.g., AUX_(n))generated based on the near-end audio captured by the microphones ofthat device 302 (e.g., MIC_(n)) and the far-end audio received via thecommunications interface 306 of that device 302 (e.g., EXT_(n)), alongwith any auxiliary audio output signals received at that device 302, viathe multichannel link, from one or more of the conferencing devices 302coupled thereto (e.g., AUX_(n−1), AUX_(n+1), etc.). In this manner, eachconferencing device 302 may receive the audio signals captured orreceived by each other conferencing device 302 within the conferencingsystem 300.

More specifically, in the illustrated embodiment, conferencing device Ais in a first position of the daisy-chain configuration and is connectedto device B. Accordingly, conferencing device A may be configured tocommunicate (e.g., transmit and/or receive) using only the secondconnection port that is coupled to device B. As shown in FIG. 3,conferencing device A may be configured to generate, for output todevice B only, a local audio output signal (e.g., AUX_(A)) comprising anear-end audio mix, which includes the microphone signals captured bythe microphones of device A (e.g., MIC_(A)), and a far-end audio mix,which includes the external audio signals received from the externalcommunication device(s) coupled to the communication interface 306 ofdevice A (e.g., EXT_(A)).

Conferencing device B, on the other hand, is in a second or middleposition and therefore, is connected to both device A, via a first cablecoupled to the first connection port of device B, and conferencingdevice C, via a second cable coupled to the second connection port ofdevice B. As shown in FIG. 3, conferencing device B may be configured togenerate, for output to the other conferencing devices A and C, a localaudio output signal (e.g., AUX_(B)) comprising a near-end audio mix,which includes the microphone signals captured by its own microphones(e.g., MIC_(B)), and a far-end audio mix, which includes the externalaudio signals received from the external communication device(s) coupledto the communication interface 306 of device B (e.g., EXT_(B)). Inaddition, conferencing device B may be configured to receive theauxiliary audio output signal of device A (e,g., AUX_(A)), via the firstcable, and output or provide the received signal to conferencing deviceC via the second cable. For example, as shown in FIG. 3, the auxiliaryaudio output signal received from device A may be combined with thelocal audio output signal generated by device B to create a mixed audiooutput signal (e.g., AUX_(AB)) for transmission to device C.

As also shown in FIG. 3, conferencing device C is in a third or endposition of the daisy-chain and therefore, is connected to device Bonly, via the second cable being coupled to its first connection port.In embodiments, conferencing device C may utilize the multi-channel linkprovided between the digital audio bus of device C and the digital audiobus of device B, via the second cable, to output or provide audiosignals back to device B. For example, conferencing device C may beconfigured to generate, for output to device B, a local audio outputsignal (e.g., AUX_(C)) comprising a near-end audio mix, which includesthe microphone signals captured by the microphones of device C (e.g.,MIC_(C)), and a far-end audio mix, which includes the external audiosignals received from the external communication device(s) coupled tothe communication interface of device C (e.g., EXT_(C)).

As also shown in FIG. 3, conferencing device B may, in turn, provide theaudio output signal received from device C (e.g., AUX_(C)) toconferencing device A, using the multi-channel link created between thedigital audio buses of the two devices B and A. For example, theauxiliary audio output signal from device C (e.g., AUX_(C)) and thelocal audio output signal generated by device B (e.g., AUX_(B)) may becombined into a mixed audio output signal (e.g., AUX_(BC)) fortransmission to device A. In this manner, the near-end signals capturedby, and/or the far-end signals received at, the end device C may beshared with each of the other conferencing devices A and B within thedaisy-chain configuration.

Other techniques for transmitting the audio output signals generated byeach conferencing device 302 to every other conferencing device 302within the system 300 are also contemplated. For example, in otherembodiments, the conferencing devices 302 may be coupled to each otherin a ring configuration wherein the second connection port ofconferencing device C is coupled to the first connection port ofconferencing device A. In such cases, the audio output signal generatedby device C (e.g., AUX_(C)) may be transmitted to device A directly, andconferencing device A may be configured to forward the AUX_(C) signal todevice B along with the AUX_(A) signal.

In other example embodiments, the audio output signals generated by eachof the devices 302 may be individually placed on the digital audio bususing the TDM slot assigned to each device 302 and may be accessible toall devices 302 within the system 300, as described herein. In suchcases, each device 302 can select, ad-hoc, which signals or sub-mixes toretrieve from the digital audio bus and create their own audio mixesinternally. For example, instead of receiving a mixed audio outputsignal AUX_(BC) from device B, device A may individually retrieve theexternal audio output signal EXT_(B) generated by device B and theexternal audio output signal EXT_(C) generated by device C and create amixed external audio output signal EXT_(BC) for output to the far-end.Likewise, device A may individually retrieve microphone signals MIC_(B)and MIC_(C) and combine those signals with its own microphone signalMIC_(A) to generate the global mixed microphone signal MIC_(ABC).

As also shown in FIG. 3, each conferencing device 302 may also beconfigured to output a far-end audio output signal (e.g., FE_(n)), viathe communication interface 306 included therein, to each of the one ormore external communication devices coupled to that device 302. Eachexternal communication device may, in turn, provide the received far-endoutput signal (e.g., FE_(n)) to the one or more far-end devicescommunicatively coupled to it. In embodiments, the far-end audio outputsignal (e.g., FE_(n)) provided to each external communication device mayinclude a common global near-end audio mix (e.g., MIC_(Global)) thatincludes the near-end audio captured by all microphones within theconferencing system 300, but a different external audio mix depending onthe specific external communication device and/or far-end device that isultimately receiving the signal. For example, each conferencing device302 may be configured to generate, for each far-end device connected tothe conference call via the communication interface 306 of that device302, an external audio mix that includes the external audio signalsreceived from each of the other far-end devices connected to theconference call via the same communication interface 306 (e.g.,EXT_(n*)), as well as the far-end audio mix received from each of theother conferencing devices 302 within the daisy-chained system 300(e.g., EXT_(n−1), EXT_(n+1), etc.). In some embodiments, eachconferencing device 302 may be configured to use matrix-mixingtechniques to remove any redundant external audio signals, or thosefar-end signals that were contributed by the same device that isreceiving the signal, from the external audio mix before outputting thefar-end audio output signal (e.g., FE_(n)) to each externalcommunication device.

For example, conferencing device A may be configured to output to eachexternal communication device coupled to its communication interface afar-end audio output signal (e.g., FE_(A)) comprising a global near-endaudio mix that includes the near-end audio signals captured by themicrophones of all three devices A, B, and C (e.g., MIC_(ABC)) and anexternal audio mix that includes the far-end audio mix for conferencingdevices B and C (e.g., EXT_(BC)) and the external audio signals receivedfrom each of the other far-end devices connected to the same externalcommunication device and/or one of the other external communicationdevices coupled to the communication interface 306 of device A (e.g.,EXT_(A*)). Similarly, conferencing device B may be configured to outputto each external communication device coupled to its communicationinterface 306 a far-end audio output signal (e.g., FE_(B)) comprisingthe global near-end mix (e.g., MIC_(ABC)) and an external audio mix thatincludes the far-end audio mix for conferencing devices A and C (e.g.,EXT_(AC)) and the external audio signals received from each of the otherfar-end devices connected to the same external communication deviceand/or one of the other external communication devices coupled to thecommunication interface 306 of device B (e.g., EXT_(B*)). Likewise,conferencing device C may be configured to output to each far-end devicecoupled to its communication interface 306 a far-end audio output signal(e.g., FE_(C)) comprising the global near-end audio mix (e.g.,MIC_(ABC)) and an external audio mix that includes the far-end audio mixfor conferencing devices A and B (e.g., EXT_(AB)) and the external audiosignals received from each of the other far-end devices connected to thesame external communication device and/or one of the other externalcommunication devices coupled to the communication interface 306 ofdevice C (e.g., EXT_(C*)).

As will be appreciated, if one of the conferencing devices 302 iscoupled to only one external communication device and that externalcommunication device is connected to only one far-end device, then theexternal audio mix included in the far-end audio output signal (e.g.,FE_(n)) will only include the far-end audio mix received from the otherconferencing devices 302 (e.g., EXT_(n−1), EXT_(n+1), etc.). On theother hand, if the external communication device is connected to two ormore far-end devices, then the conferencing device 302 may output twodifferent far-end audio output signals, each comprising a differentexternal audio mix tailored to the specific far-end receiving device.Also, if one of the conferencing devices 302 is not coupled to anyexternal communication devices via its communication interface 306, thena far-end audio output signal may not be generated by that device 302.

As also shown in FIG. 3, each conferencing device 302 may be configuredto output a loudspeaker signal (e.g., LS_(n)) via its loudspeaker 304 toany near-end participants within audible range of the device 302. Theloudspeaker signal (e.g., LS_(n)) generated by each conferencing device302 may comprise a global far-end audio mix (e.g., EXT_(Global)) thatincludes all of the far-end audio signals received at the communicationinterfaces 306 of the conferencing devices 302 within the system 300, aswell as a near-end audio mix comprising the near-end audio signalsreceived from the other conferencing devices 302 (e.g., MIC_(n−1),MIC_(n+1), etc.). In some embodiments, the near-end audio signalsreceived from the other conferencing devices 302 may be gain-adjusted orotherwise modified based on a proximity to the receiving device 302(e.g., MIC*_(n)), so that distant voices are “lifted” or reinforced ascompared to nearby voices until all voices or signals are played at auniform signal level or strength, as described in more detail herein.For example, the near-end audio signals received from immediatelyadjacent conferencing devices 302 (e.g., MIC_(n−1) or MIC_(n+1)) may beattenuated more than the near-end audio signals received fromconferencing devices 302 that are further away from the receiving device302 along the daisy-chain (e.g., MIC_(n+2), MIC_(n−2), MIC_(n+3),MIC_(n−3), etc.).

In the illustrated example, conferencing device A generates an audiosignal for output by its loudspeaker 304 (e.g., LS_(A)) that comprises aglobal far-end audio mix (e.g., EXT_(ABC)), which includes a mix of thefar end audio signals received from all of the external communicationdevices coupled to each of the conferencing devices A, B, and C, and anear-end audio mix, which includes a gain-adjusted version of thenear-end audio signals captured by the microphone(s) of conferencingdevice B (e.g., MIC*_(B)) and a gain-adjusted version of the near-endaudio signals captured by the microphone(s) of conferencing device C(e.g., MIC*_(C)). In some embodiments, the gain-adjustment may includesubstantially or completely attenuating the near-end audio signalreceived from device B (e.g., MIC_(B)) because conferencing device B maybe close enough to device A that little or no gain adjustment isnecessary to improve intelligibility. The gain-adjustment may alsoinclude amplifying the near-end audio signal received from device C(e.g., MIC_(C)), since device C may be far enough away from device Athat a relative gain adjustment is required.

Similarly, conferencing device B generates a loudspeaker audio signal(e.g., LS_(B) for output by its loudspeaker 304 that comprises theglobal far-end audio mix (e.g., EXT_(ABC)) and a near-end audio mixincluding a gain-adjusted version of the near-end audio signals capturedby the microphone(s) of conferencing device A (e.g., MIC*_(A)) and asecond gain-adjusted version of the near-end audio signals captured bythe microphone(s) of conferencing device C (e.g., MIC*_(C)). Inembodiments, the amount of gain adjustment applied to the near-end audiosignals received from devices A and C (e.g., MIC_(A) and MIC_(C)) may bethe same or similar if the two devices A and C are generally equidistantfrom the middle device B. For example, in one embodiment, both near-endaudio signals may be substantially or completely attenuated because bothdevices A and C are positioned close enough to the conferencing device Bthat little or no gain-adjustment is necessary.

Likewise, conferencing device C generates a loudspeaker audio signal(e.g., LS_(C)) for output by its loudspeaker 304 that comprises theglobal far-end audio mix (e.g., EXT_(ABC)) and a near-end audio mix thatincludes a second gain-adjusted version of the near-end audio signalscaptured by the microphone(s) of conferencing device A (e.g., MIC*_(A))and a second gain-adjusted version of the near-end audio signalscaptured by the microphone(s) of conferencing device B (e.g., MIC*_(B)).In embodiments, the gain-adjustment may include substantially orcompletely attenuating the near-end audio signal received from device B(e.g., MIC_(B)), since conferencing device B may be close enough todevice C that little or no gain adjustment is necessary. Thegain-adjustment may also include amplifying the near-end audio signalreceived from device A (e.g., MIC_(A)), since device A may be far enoughaway from device C that a relative gain adjustment is required.

In cases where there are no remote participants to a meeting, none ofthe conferencing devices 302 may be coupled to an external communicationdevice, and no far-end audio signals may be received at thecommunication interface 306 of each conferencing device 302. In suchcases, the loudspeaker audio signal generated for each conferencingdevice 302 may comprise only gain-adjusted near-end audio signalsreceived from the other conferencing devices 302 within the system 300.Also, the digital audio bus of each conferencing device 302 may be usedto transmit only near-end audio signals between the daisy-chaineddevices 302. Gain-adjustment techniques may still be applied to thenear-end audio signals before generating the loudspeaker signal, so thatthe voices of each participant in the meeting can be uniformly played orheard throughout the conferencing environment, especially in large boardrooms or other expansive meeting spaces, for example.

Referring additionally to FIG. 4, shown is a functional block diagram ofan exemplary conferencing device 400 for facilitating a conference call,video conference, webinar, or other meeting between multipleparticipants in separate and/or large conferencing spaces, in accordancewith embodiments. The conferencing device 400 may represent or besimilar to one or more of the conferencing devices 102/200/302 describedherein, for example, in terms of operation and/or individual components.In addition, the conferencing device 400 may be coupled to one or moreother conferencing devices in series, so as to form a daisy-chain orline topology for exchanging audio signals and other information betweenthe devices, similar to the daisy-chain configurations of FIGS. 1 and/orFIG. 3, for example. Each of the other conferencing devices within thedaisy-chain may be the same as or similar to the conferencing device400, and all of the daisy-chained conferencing devices may cooperate toform a conferencing system, similar to the conferencing system 300 ofFIG. 3, for example.

According to the illustrated embodiment, the conferencing device 400 maybe configured to receive one or more near-end audio signals from one ormore near-end audio sources 402 included in or communicatively connectedto the device 400. As an example, the near-end audio sources 402 mayinclude four microphones MIC1, MIC2, MIC3, and MIC4 for detecting andcapturing speech or other sounds produced by near-end or in-roomparticipants and converting the sounds into audio signals (also referredto herein as “microphone signals). In other embodiments, theconferencing device 400 may include more or fewer microphones, or othertypes of near-end audio sources.

The conferencing device 400 may also be configured to receive one ormore external audio signals from one or more far-end audio sources 404of the conferencing device 400. For example, the far-end audio sources404 may include input connections to one or more external communicationports (or a communication interface) communicatively coupled to one ormore external communication devices (such as, e.g., externalcommunication devices 106 shown in FIG. 1) for receiving, from one ormore remote devices, audio signals representing speech or other soundsproduced by remote or far-end participants. The external communicationsports may include, for example, a Bluetooth® transceiver (“BT In”), aUSB port (“From USB”), and an audio input/output port (“Line In”).

The conferencing device 400 may also include a near-end output device406, such as, e.g., a loudspeaker or other speaker device, for providingan audio output to one or more in-room participants. In addition, theconferencing device 400 may be configured to provide an audio output toone or more remote participants via one or more far-end outputs 408,which may be coupled to corresponding external communication ports ofthe device 400. For example, the far-end outputs 408 may include outputconnections to the USB port (“To USB”), the audio input/output port(“Line Out”), the Bluetooth® transceiver (“BT Out”), and/or any otherexternal communication ports. Also, the conferencing device 400 mayinclude a digital audio bus 410 and a pair of local connection portscoupled thereto (such as, e.g., first connection port 224 and secondconnection port 226 shown in FIG. 2) for physically connecting theconferencing device 400 to one or more other conferencing devices in thedaisy-chain configuration, as described herein.

As shown in FIG. 4, the conferencing device 400 includes a microphonemixing module 412 for processing the microphone signals output by themicrophones 402 and generating a local microphone mix representing allsounds detected by the microphones MIC1, MIC2, MIC3, and MIC4, forexample. In some embodiments, the microphone mixing module 412 may beconfigured to control incoming signal amplitude or gain, convert analogsignals to digital form, apply acoustic echo cancellation and noisereduction techniques, apply automixing techniques, and/or perform othersignal processing tasks for generating the local microphone mix. Themicrophone mixing module 412 may be implemented, for example, usingsoftware executed by one or more processor, firmware hosted by one ormore digital signal processors, and/or hardware. The local microphonemix (such as, e.g., MIC_(n) of FIG. 3) may be provide to a far-endmixing module 414, which generates a far-end output signal (e.g., FEE ofFIG. 3) based on the local microphone mix and other inputs describedherein. The local microphone mix may also be provided to the digitalaudio bus 410 for transmission to the other conferencing devices in thedaisy-chain, as shown in FIG. 4. In some cases, the microphone mixingmodule 412 may receive a reference signal from the near-end output 406for echo cancellation purposes. As shown in FIG. 4, the reference signalmay include the loudspeaker signal provided to near-end output 406, soas to prevent echo of the near-end voices when the local microphone mixis transmitted to the far-end outputs 408.

The external audio signals received from the far-end audio sources 404may also be provided to the far-end mixing module 414 for inclusion inthe far-end output signal, which may be transmitted to each of thefar-end outputs 408. In embodiments, the far-end mixing module 414 mayemploy matrix-mixing techniques to generate a different external audiomix for each far-end output 408, so that the external audio signalreceived via one external communication port is not transmitted backthrough the same external communication port (such as, e.g., EXT_(n*) ofFIG. 3). For example, the external audio mix provided to the Bluetooth®transceiver (e.g., BT Out) may not include the external audio signalsreceived via the same source (e.g., BT In). Similarly, the externalaudio mix provided to the audio input/output port (e.g., Line Out) maynot include the external audio signals received via the same port (e.g.,Line In). And the external audio mix provided to the USB port (e.g., ToUSB) may not include the external audio signals received via the sameport (e.g., From USB).

In embodiments, each conferencing device, including the conferencingdevice 400, may generate a local audio output signal for output to theother conferencing devices along the daisy-chain using the digital audiobus connections and other techniques described herein. The local audiooutput signal provided by each conferencing device (such as, e.g.,AUX_(n) of FIG. 3) may include a near-end audio mix (such as, e.g.,MIC_(n) of FIG. 3) comprising the microphone signals detected by themicrophones of that conferencing device, and an external audio mix (suchas, e.g., EXT_(n) of FIG. 3) comprising the external audio signalsreceived by the far-end audio sources of the same device. In some cases,each conferencing device 400 may combine its local audio output signalwith the auxiliary audio output signals received from other conferencingdevices (such as, e.g., AUX_(n−1), AUX_(n−1), etc. of FIG. 3) via thedigital audio bus 410, to create one mixed auxiliary output signal fortransmission to one or more of the other conferencing devices coupled tothe digital audio bus 410. In other cases, the near-end audio mix andthe external audio mix may be provided as individual signals to thedigital audio bus 410 for dissemination to the other devices, withoutfirst mixing these signals together or with any auxiliary audio outputsignals received from other devices.

According to embodiments, in addition to the local microphone mix andthe customized external audio mix, the far-end output signal may alsoinclude the auxiliary audio output signals received from one or more ofthe other conferencing devices coupled to the digital audio bus 410.Each received auxiliary audio output signal may include an auxiliarynear-end mix comprising the mixed microphone signals captured by one ormore other conferencing devices in the daisy-chain and an auxiliaryfar-end mix comprising the external audio signals received by the sameone or more other conferencing devices. As shown in FIG. 4, theauxiliary far-end audio mix (also referred to as “auxiliary externalaudio mix”) and the auxiliary near-end audio mix (also referred to as“auxiliary mixed microphone signals”) may be separated from the receivedauxiliary signal and individually provided to the far-end mixing module414 for inclusion in the far-end output signal. The auxiliary far-endaudio mix may also be combined with the local far-end audio signalsreceived from the far-end audio sources 404 to generate a globalexternal audio mix (e.g., EXT_(Global)). As illustrated, this globalexternal audio mix and the auxiliary near-end audio mix may be includedin a loudspeaker signal (such as, e.g., LS_(n) of FIG. 3) that isgenerated for output to the in-room participants via the near-end audiooutput 406.

In embodiments, prior to creating the loudspeaker signal, theconferencing device 400 may be configured to apply a gain adjustmentvalue (g_(n)) to each of the auxiliary mixed microphone signals includedin the auxiliary near-end audio mix, so that all auxiliary microphonesignals are output by the loudspeaker 406 at the same signal level. Suchgain adjustments ensure that each of the other in-room participants'voices can be heard uniformly by the participants using the conferencingdevice 400, regardless of the room size or the distance betweenconferencing device 400 and other conferencing devices. The technique,also referred to as “voice lift,” may be configured to adjust the levelor strength of each auxiliary microphone signal only as needed tosupplement or enhance signal intelligibility at the conferencing device400, rather than fully reproducing the signals or increasing the overallvolume of the loudspeaker, which may be perceived as too loud ortroublesome. For example, voice lift may be applied to raise the levelof a participant speaking on the opposite end of a conferencing room ortable, but may not be applied to those participants seated near thelistener, so as to help ensure a uniform signal level for all in-roomvoices.

The voice lift technique may be implemented by amplifying or attenuatinga gain of each auxiliary mixed microphone signal before the signalreaches the near-end output 406. The amount of voice lift or gainadjustment applied may be based on a relative position of theoriginating conferencing device, for example, within the conferencingspace or within the daisy-chain sequence, as compared to the receivingconferencing device 400. As an example, the conferencing device 400 mayfirst determine a sequential order or relative location of the otherconferencing device that originally captured a given auxiliarymicrophone signal and then calculate a gain adjustment value for thatsignal based on the determined position.

In some embodiments, the conferencing device 400 may be configured toapply zoning rules to help select an appropriate amount of gainadjustment for each auxiliary microphone signal depending on its placeof origination. The zoning rules may be configured to apply graduatedattenuation to each microphone signal based on the order of thecorresponding conferencing device within the daisy-chain. For example,the zoning rules may determine that the auxiliary microphone signals ofadjacent conferencing devices need not be included, or can be largely orcompletely attenuated, in the near-end audio mix. This may be becausethe voices of in-room participants using an adjacent conferencing device(or otherwise within an adjacent zone) may be intelligible or audibleenough, as is or without reinforcement, to the in-room participantsusing the conferencing device 400. As another example, the voices ofin-room participants using more distantly positioned conferencingdevices (or otherwise within a distant zone) may be too faint to beintelligible at the conferencing device 400. In such cases, the zoningrules may proportionately adjust the gain adjustment value applied toeach auxiliary microphone signal based on the distance, or the number ofdaisy-chain positions, between the conferencing device 400 and theconferencing device providing the signal. For example, more gain may beapplied to signals received from conferencing devices that are furtherdown in the daisy-chain, and less gain may be applied to signals thatare closer to the conferencing device 400.

In some cases, the gain adjustment value may be an amount of attenuationapplied to a given auxiliary microphone signal. In other cases, the gainadjustment value may be an amount of amplification that is applied tothe auxiliary microphone signal. As will be appreciated, attenuation andamplification can be relative terms, and either or both may be impliedby the term “gain adjustment.” Other techniques for adjusting the gainof auxiliary microphone signals to achieve a uniform level are alsocontemplated. According to embodiments, gain adjustment may be appliedto the auxiliary microphone signals using appropriate software executingon one or more processors (e.g., DSP(s)), hardware (e.g., one or moreamplifiers), or a combination thereof.

In one exemplary embodiment, the conferencing device 400 may bepositioned at a first position within the daisy-chain (such as, e.g.,device A of FIG. 1) and may receive auxiliary audio signals fromconferencing devices in a second position (such as, e.g., device B ofFIG. 1), a third position (such as, e.g., device C of FIG. 1), a fourthposition (such as, e.g., device D of FIG. 1), and a fifth position (suchas, e.g., device E of FIG. 1). In such cases, using zoning rulespreselected for the daisy-chain configuration of FIG. 1, the firstconferencing device A may apply, to a first auxiliary mixed microphonesignal received from the second conferencing device B, a first gainadjustment value (g₀) that largely or completely attenuates (e.g., g₀=−∞dB) and/or applies no reinforcement to the first auxiliary mixedmicrophone signal. This gain adjustment value may be selected by thezoning rules because device B is positioned next to device A andtherefore, the first microphone signal may be intelligible to theparticipants at device A with little or no supplementing. For a secondauxiliary mixed microphone signal received from the third conferencingdevice C, the zoning rules may apply a second gain adjustment value (g₁)that is greater than g₀ (e.g., g₁=−30 dB), or provides morereinforcement and/or less attenuation than go, to the second auxiliarymixed microphone signal. In this case, at least some supplementing maybe necessary to enhance the intelligibility of the second microphonesignal because device C is two positions away from device A within thedaisy-chain order.

A third gain adjustment value (g₂) that is larger than g₁(e.g., g₂=−20dB), or provides more reinforcement and/or less attenuation than g₁, maybe applied to a third auxiliary mixed microphone signal received fromthe fourth conferencing device D. The zoning rules may require a largerreinforcement value for the third microphone signal because device D isthree positions away from device A. Finally, a fourth gain adjustmentvalue (g₃) applied to a fourth auxiliary mixed microphone signalreceived from the fifth conferencing device E may have the largest valueof all (e.g., g₃=−10), or may provide the greatest amount ofreinforcement and/or least or no attenuation. In this case, the zoningrules may require the largest reinforcement value for the fourthmicrophone signal because device E is four positions away, or furthest,from device A.

In some embodiments, the physical distance between any two conferencingdevices may be estimated, or calculated, at the time of daisy-chainorder discovery and used to determine the gain adjustment valuesdescribed above. In one example embodiment, the distance at whichadjacent conferencing devices are most likely to be spaced apart withina typical conferencing scenario may be a preset value. This preset valuefor adjacent devices may be used to infer the actual distance betweenany given pair of conferencing devices based further on the order andposition of those devices within the daisy-chain. For example, tocalculate the distance from device A to device C, the preset distancevalue may be multiplied by the difference between the daisy-chainposition of device A (e.g.,. position 1) and the daisy-chain position ofdevice C (e.g., position 3). In another example embodiment, the distancebetween any two conferencing devices may be directly calculated usingacoustical measurements taken from one device to the next using acousticprocessing techniques, as will be appreciated.

FIGS. 5 and 6 illustrate exemplary methods 500 and 600 for processing aplurality of audio signals associated with a conferencing environment(such as, e.g., conferencing environment 100 shown in FIG. 1) comprisinga plurality of conferencing devices (such as, e.g., conferencing devices102 shown in FIG. 1) connected to each other or arranged in adaisy-chain configuration, in accordance with embodiments. The methods500 and 600 may be performed using a first one of the conferencingdevices (such as, e.g., conferencing device 200 shown in FIG. 2).

Each of the plurality of conferencing devices may comprise at least onemicrophone (such as, e.g., microphone(s) 202 shown in FIG. 2), at leastone loudspeaker (such as, e.g., loudspeaker 204 shown in FIG. 2), atleast one processor (such as, e.g., processor(s) 208 shown in FIG. 2),one or more external communication ports (such as, e.g., communicationinterface 206 comprising ports 216, 218, and 222, as shown in FIG. 2)for connecting to one or more external communication devices (such as,e.g., external communication devices 106 shown in FIG. 1, and a pair oflocal connection ports (such as, e.g., local connection ports 224 and226 shown in FIG. 2) for connecting to one or more of the otherconferencing devices within the environment.

As described herein, the plurality of conferencing devices may beconnected to each other in series or “end-to-end,” for example, bycoupling a first local connection port of each conferencing device to asecond local connection port of another conferencing device (e.g., usingcables 110 shown in FIG. 1) until each conferencing device is connectedto at least one other conferencing device, thus forming a daisy-chain(e.g., as shown in FIGS. 1 and 3). In embodiments, each conferencingdevice further comprises a digital audio bus (e.g., digital audio bus214 shown in FIG. 2) configured to facilitate communication with (orbetween) the first and second local connection ports, as well as the oneor more processors of the conferencing device, and facilitate formationof the daisy-chain configuration. As also described herein, theconferencing devices may be configured to leverage this daisy-chainconfiguration to quickly and efficiently communicate audio signals andother information with each other.

In embodiments, the methods 500 and 600 may be utilized to process audiosignals for carrying out one or more of the operations described hereinand shown in the figures, such as, for example, FIGS. 3 and 4. Forexample, method 500 may be used to process audio signals received fromone or more sources and based thereon, generate a loudspeaker outputsignal for the loudspeaker of the conferencing device. Method 600 may beused to process audio signals received from one or more sources andbased thereon, generate a first mixed audio output signal fortransmission through one or more of the local connection ports of theconferencing device and a second mixed audio output signal fortransmission through one or more of the external communication ports ofthe conferencing device. One or more processors and/or other processingcomponents (e.g., analog to digital converters, encryption chips, etc.)within or external to the conferencing device may perform any, some, orall of the steps of the methods 500 and/or 600. One or more other typesof components (e.g., memory, input and/or output devices, transmitters,receivers, buffers, drivers, discrete components, etc.) may also beutilized in conjunction with the processors and/or other processingcomponents to perform any, some, or all of the steps of the methods 500and/or 600.

Method 500 may begin at step 502 with identifying one or moreconnections to the one or more other conferencing devices at the localconnection ports of a given conferencing device (also referred to hereinas “the first conferencing device”). For example, the conferencingdevice may be configured to identify the presence or absence of aphysical connection at each of the local connection ports. In someembodiments, identifying the one or more connections to otherconferencing devices includes identifying characteristics about orassociated with the one or more connections, such as, for example, theorder or daisy-chain position of the other device connected to a givenlocal connection port. In such cases, the conferencing devices may sharetheir order within the daisy-chain (e.g., first, second, third, etc.)with the other conferencing devices coupled thereto, e.g., via thedigital audio bus. For example, each conferencing device may send itsposition within the daisy-chain to the other conferencing device coupledto its second local connection port, if any, and/or may receive positioninformation at the first local connection port from the otherconferencing device coupled thereto, if any.

At step 504, a position of the given conferencing device within thedaisy-chain configuration may be determined upon identifying the one ormore connections, or based thereon. In some embodiments, the digitalaudio bus is used to automatically and dynamically determine theposition of the given device within the daisy-chain configuration usinga self-discovery protocol, as described herein. For example, if thedigital audio bus identifies a connection at a first connection port(e.g., “OUT”) of the given device but no connection at a secondconnection port (e.g., “IN”), then the digital audio bus may determinethat the given conferencing device is at the beginning of thedaisy-chain, or in the first position. Conversely, if the digital audiobus identifies a connection at the second connection port but noconnection at the first connection port, then the digital audio bus maydetermine that the given conferencing device is at the end of thedaisy-chain, or in the last position. Alternatively, if the digitalaudio bus identifies connections at both of the local connection ports,then the daisy-chain order of the given conferencing device may bedetermined by sequentially incrementing the order of the immediatelypreceding device, or the conferencing device coupled to the secondconnection port of the first conferencing device. For example, if theother conferencing device coupled to the second connection port isidentified as being in the third position of the daisy-chain, the firstconferencing device will assign itself to the fourth position. Usingsimilar steps, the other conferencing device coupled to the firstconnection port of the first conferencing device may assign itself tothe fifth position of the daisy-chain, and so on.

In other embodiments, one of the plurality of conferencing devices maybe assigned as a “master device,” while the rest of the conferencingdevices may be assigned as “slave devices.”

In such cases, the master device may be tasked with assigningdaisy-chain positions to each of the slave devices using a serialdiscovery process and sending daisy-chain position information to eachof the other conferencing devices, as described herein. For example, themaster status may be automatically assigned to the device that occupiesthe first position within the daisy-chain. The master device mayidentify or discover the first slave device by determining which deviceis connected to its first connection port. That first slave device willbe assigned the second daisy-chain position. The master device may thenidentify which slave device is connected to the first connection port ofthe first slave device and assign that second slave device to the thirddaisy-chain position, and so forth. Each of the slave devices may beassigned a corresponding sequential identifier, which signifies theirorder of discovery and configures them as slave nodes on the digitalaudio bus. These sequential identifiers may be shared across the digitalaudio bus and used by each conferencing device to determine their owndaisy-chain position as well as the positions of their neighbors andother devices.

Once the daisy-chain position of the given conferencing device has beendetermined, the method 500 may continue to steps 506, 508, and/or 510.In some cases, the method 500 may begin at these steps, such as, forexample, in scenarios where the daisy-chain position of the givenconferencing device was previously determined (e.g., at start-up) and nochanges to the daisy-chain are anticipated or detected. In other cases,the method 500 may always begin at step 502, so as to confirm the givenconferencing device's current daisy-chain position before proceeding tosteps 506/508/510.

At step 506, the given conferencing device receives one or moreauxiliary mixed microphone signals (such as, e.g., MIC_(n−), MIC_(-n+1),etc. of FIG. 3) from at least one of the local connection ports. Each ofauxiliary mixed microphone signal may comprise a mix of the microphonesignals captured by a respective one of the other conferencing deviceswithin the daisy-chain. At step 508, the given conferencing devicereceives one or more auxiliary mixed external audio signals (such as,e.g., EXT_(n−1), EXT_(n+1), etc. of FIG. 3) from at least one of thelocal connection ports. Each auxiliary mixed external audio signal maycomprise a mix of the far-end or external audio signals received by arespective one of the other conferencing devices within the daisy-chain.

In some embodiments, steps 506 and 508 may occur substantiallysimultaneously, or may be combined into one step, for example, in caseswhere the auxiliary mixed microphone signals and the auxiliary mixedexternal audio signals are combined and transmitted as an auxiliaryaudio mix (such as, e.g., AUX_(n−1), AUX_(n+2), etc. of FIG. 3). Inother embodiments, steps 506 and 508 may occur independently, forexample, primarily depending on when the respective near-endparticipants and/or far-end participants communicatively connected to,or associated with, the other conferencing devices decide to contributeto the conference call. In still other embodiments, the firstconferencing device may not receive any auxiliary mixed external audiosignals, for example, if there are no external communication devicescoupled to the other conferencing devices within the daisy-chain. Insuch cases, the method 500 may not include step 508.

As an example, one of the auxiliary audio signals received at steps 506and/or 508 may be provided by the other conferencing device that islocated at the immediately preceding position and is connected to theinput connection port of the first conferencing device (such as, e.g.,AUX⁻¹ of FIG. 3). Another of the auxiliary audio signals received atsteps 506 and/or 508 may be provided, for example, by the otherconferencing device that is located at the immediately succeedingposition and is connected to the output connection port of the firstconferencing device (such as, e.g., AUX_(n+1) of FIG. 3). As anotherexample, one of the auxiliary audio signals received at steps 506 and/or508 may be provided by the other conferencing device that is located atthe end position of the daisy-chain and/or is not physically connectedto one of the local connection ports (such as, e.g., AUX_(n+2) in FIG.3). In each of these examples, the auxiliary audio signals may betransmitted from device to device or via the multi-channel link createdupon connecting the digital audio buses of all the conferencing devicesin series (e.g., as shown in FIG. 3).

At step 510, the given conferencing device receives one or more localexternal audio signals (such as, e.g., EXT_(n) of FIG. 3) at the one ormore external communication ports. In embodiments, step 510 may occurindependently of steps 506 and 508, for example, depending primarily onwhen the respective far-end participants communicatively connected to orassociated with the given conferencing device decide to contribute tothe conference call. In some embodiments the first conferencing devicemay not receive any local external audio signals, for example, if thereare no external communication devices coupled to the given conferencingdevice. In such cases, the method 500 may not include step 510.

If steps 508 and/510 are performed, the method 500 may further includestep 512, wherein a global external audio signal (such as, e.g.,EXT_(Global) of FIG. 3) is generated by mixing any auxiliary mixedexternal audio signals received at step 508 and/or any local externalaudio signals received at step 510. And from step 506, the method 500may continue to step 514. As shown in FIGS. 5 and 6, steps 506, 508, and510 may also serve as inputs to or steps of the method 600, as will bedescribed in more detail herein.

At step 514, a gain adjustment value is determined for each of the oneor more auxiliary mixed microphone signals based on a position of thecorresponding other conferencing device within the daisy-chainconfiguration relative to a position of the given conferencing device.At step 516, a gain value for each of the one or more auxiliary mixedmicrophone signals is adjusted based on the corresponding gainadjustment value determined at step 514, thus creating a gain-adjustedversion of each signal. In embodiments, the gain-adjustment value may beselected to reinforce, or raise the level of, voice signals that arelocated far from the given conferencing device (e.g., on the other sideof the room) and therefore, have poor intelligibility at the location ofthat device. In embodiments, the gain adjustment value for each of theone or more auxiliary mixed microphone signals may be proportional to adistance between the given conferencing device and the correspondingother conferencing device. In some cases, gain adjustment values may beapplied on a graduated scale depending on this distance and/or adifference in the daisy-chain positions of each conferencing device.

For example, determining the gain adjustment value for each auxiliarymicrophone signal may include identifying a first auxiliary mixedmicrophone signal as being received from another, or second,conferencing device positioned adjacent to the given, or first,conferencing device within the daisy-chain configuration, and selectinga first gain adjustment value that decreases a strength of, orattenuates, the first auxiliary mixed microphone signal based on theidentified position of the second conferencing device. In some cases,the level of the first signal may be completely attenuated or excludedfrom the near-end audio mix because the second conferencing device isclose enough to the first conferencing device that reinforcement of thefirst signal is not required.

As another example, determining the gain adjustment value for each ofthe one or more auxiliary mixed microphone signals may further includeidentifying a second auxiliary mixed microphone signal as being receivedfrom yet another, or a third, conferencing device positionednon-adjacent to the first conferencing device within the daisy-chainconfiguration, and selecting a second gain adjustment value that adjustsa strength, or signal level, of the second auxiliary mixed microphonesignal based on the identified position of the third conferencingdevice. In such cases, the second gain adjustment value may adjust thestrength of the second auxiliary mixed microphone signal to be abovethat of the first auxiliary mixed microphone signal. In some cases, thisadjustment may be configured to adjust the second auxiliary microphonesignal to a level that is substantially similar to a signal level oflocal microphone signals captured by the microphones of the firstconferencing device (e.g., in step 602 of FIG. 6), so that the voices ofall in-room participants may be heard uniformly across the conferencingroom or space.

Step 518 includes generating a loudspeaker output signal (such as, e.g.,LS_(n) of FIG. 3) by mixing the one or more gain-adjusted auxiliarymixed microphone signals (e.g., MIC*_(n−1), MIC*_(n−1), etc. of FIG. 3)and the global external audio signal generated at step 512, if any. Step520 includes providing the loudspeaker output signal to the loudspeakerof the given or first conferencing device for output to the in-roomparticipants that are seated around, or are within audible range of, thefirst conferencing device. In embodiments, the given conferencing devicemay produce at least two other outputs, besides the loudspeaker outputsignal, as shown in FIG. 6.

More specifically, method 600 may begin at step 602 with receiving oneor more local microphone signals from the at least one microphoneincluded in the given conferencing device. For example, the microphones(such as, e.g., MIC1, MIC2, MIC3, and MIC4 shown in FIG. 4) may beconfigured to capture near-end audio, such as speech or other sounds,produced by one or more in-room participants (such as, e.g., near-endparticipants 104 shown in FIG. 1) located within a predetermineddetection rage of the given conferencing device. At step 604, a localmixed microphone signal, or near-end audio mix, (such as, e.g., MICE_(n)of FIG. 3) may be generated by mixing (e.g., automixing) the localmicrophone signals into one signal (or channel), using, for example MICmixing module 412 of FIG. 4.

At step 606, a local mixed external audio signal (such as, e.g., EXT_(n)of FIG. 3) may be generated by mixing the local external audio signalsreceived from the external communication ports at step 510 of method500. At step 608, the local mixed external audio signal generated atstep 606 and the local mixed microphone signal generated at step 604 maybe provided to at least one of the local connection ports fortransmission to the other conferencing devices within the daisy-chainvia the digital audio bus. In some embodiments, the local audio signalsmay be mixed into one auxiliary signal (such as, e.g., AUX_(n) of FIG.3) prior to transmission, or may be transmitted individually via thedigital audio bus.

In some embodiments, the method 600 includes step 610, where anyauxiliary mixed external audio signals received at step 508 of method500 and the auxiliary mixed microphone signals received at step 506 ofmethod 500 are provided to at least one of the local connection portsfor transmission to the other conferencing devices within thedaisy-chain via the digital audio bus. In other embodiments, forexample, where the auxiliary signals are shared on the digital audio bususing TDM slots and therefore, are already accessible to the otherdevices, step 610 may not be performed.

In some embodiments, steps 608 and 610 may be performed substantiallysimultaneously or as one step, for example, by providing a single mixcomprising all audio to be output to the respective local connectionport. In other embodiments, the auxiliary audio mixes (e.g., comprisingauxiliary microphone and/or external audio signals) received at one ofthe local connection ports may be provided directly to the other localconnection port for transmission to the other conferencing devicecoupled thereto, as needed. And the local audio mix (e.g., comprisinglocal microphone and/or external audio signals) may be provided to oneor both of the local connection ports, depending on the order of thegiven conference device, for transmission throughout the daisy-chain.For example, the conferencing device in the first position of thedaisy-chain may only be connected to the conferencing device in thesecond position, via a first local connection port. This connection mayserve as an upstream link for transmitting the local audio mix generatedby the first position device to the second position device and adownstream link for receiving auxiliary audio mixes from the otherconferencing devices within the daisy-chain via the second positiondevice. If the conferencing device is positioned in the middle of thedaisy-chain, the local audio mix generated by that conferencing devicemay be provided to both local connection ports for upstream anddownstream transmission to the other conferencing devices. Likewise, theauxiliary audio mixes provided by the other conferencing devices may bereceived at both local connection ports, since the other devices arelocated both upstream and downstream.

Step 612 includes, for each of the one or more external communicationports, generating a far-end output signal (such as, e.g., FE_(n) of FIG.3) by mixing the local mixed microphone signal generated at step 604,the one or more auxiliary mixed microphone signals received at step 506of method 500, the one or more auxiliary mixed external audio signalsreceived at step 508 of method 500, and the local external audio signalsreceived from each of the other external communication ports at step 510of method 500, if any. Step 614 includes providing the far-end outputsignal to the respective external communication port. In embodiments, adifferent far-end output signal may be generated for each externalcommunication port in order to ensure that the external audio signalreceived at a given external communication port is not output backthrough the same port, for example, using the far end mixing module 414shown in FIG. 4.

The method 500 may end upon completion of step 520, and the method 600may end upon completion of step 614.

Any process descriptions or blocks in figures should be understood asrepresenting modules, segments, or portions of code which include one ormore executable instructions for implementing specific logical functionsor steps in the process, and alternate implementations are includedwithin the scope of the embodiments of the invention in which functionsmay be executed out of order from that shown or discussed, includingsubstantially concurrently or in reverse order, depending on thefunctionality involved, as would be understood by those having ordinaryskill in the art.

This disclosure is intended to explain how to fashion and use variousembodiments in accordance with the technology rather than to limit thetrue, intended, and fair scope and spirit thereof. The foregoingdescription is not intended to be exhaustive or to be limited to theprecise forms disclosed. Modifications or variations are possible inlight of the above teachings. The embodiment(s) were chosen anddescribed to provide the best illustration of the principle of thedescribed technology and its practical application, and to enable one ofordinary skill in the art to utilize the technology in variousembodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the embodiments as determined by the appendedclaims, as may be amended during the pendency of this application forpatent, and all equivalents thereof, when interpreted in accordance withthe breadth to which they are fairly, legally and equitably entitled.

What is claimed is:
 1. A method of processing a plurality of audiosignals associated with a conferencing environment comprising aplurality of conferencing devices connected in a daisy-chainconfiguration, using a first one of the conferencing devices, the firstconferencing device comprising at least one microphone, at least oneloudspeaker, at least one processor, one or more external communicationports for connecting to one or more external communication devices, anda pair of local connection ports for communicatively connecting to atleast one other conferencing device, the method comprising: receivingone or more auxiliary mixed microphone signals from at least one of thelocal connection ports, each of the one or more auxiliary mixedmicrophone signals comprising a mix of microphone signals captured by arespective one of the other conferencing devices; determining, using atleast one processor, a gain adjustment value for each auxiliary mixedmicrophone signal based on a position of the other conferencing devicethat captured the signal, relative to a position of the firstconferencing device within the daisy-chain configuration; adjusting,using at least one processor, a gain value for each auxiliary mixedmicrophone signal based on the corresponding gain adjustment value;generating, using at least one processor, a loudspeaker output signalfrom the one or more gain-adjusted auxiliary mixed microphone signals;and providing the loudspeaker output signal to the at least oneloudspeaker of the first conferencing device.
 2. The method of claim 1,further comprising: determining, using at least one processor, theposition of the first conferencing device within the daisy-chainconfiguration upon identifying one or more connections to the one ormore other conference devices at one or more of the local connectionports.
 3. The method of claim 2, wherein the first conferencing devicefurther comprises a digital audio bus configured to facilitatecommunication with the local connection ports and determination of theposition of the first conferencing device with the daisy-chainconfiguration.
 4. The method of claim 1, further comprising: receivingone or more local external audio signals at the one or more externalcommunication ports; generating, using at least one processor, a localmixed external audio signal from the one or more local external audiosignals; and providing the local mixed external audio signal to at leastone of the local connection ports.
 5. The method of claim 4, furthercomprising: receiving one or more auxiliary mixed external audio signalsfrom at least one of the local connection ports, each auxiliary mixedexternal audio signal comprising a mix of external audio signalsreceived by a respective one of the other conferencing devices; andgenerating, using at least one processor, a global mixed external audiosignal by mixing the one or more local external audio signals and theone or more auxiliary mixed external audio signals, wherein generatingthe loudspeaker output signal further includes mixing the one or moregain-adjusted auxiliary microphone signals with the global mixedexternal audio signal.
 6. The method of claim 5, further comprising:receiving one or more local microphone signals from the at least onemicrophone included in the first conferencing device; generating, usingat least one processor, a local mixed microphone signal from the one ormore local microphone signals; providing the local mixed microphonesignal to at least one of the local connection ports; and for each ofthe one or more external communication ports: generating, using at leastone processor, a far-end output signal from the local mixed microphonesignal, the one or more auxiliary mixed microphone signals, the one ormore auxiliary mixed external audio signals, and the one or more localexternal audio signals received from each other external communicationport, and providing the far-end output signal to the respective externalcommunication port.
 7. The method of claim 6, wherein the one or moreauxiliary mixed microphone signals and the one or more auxiliary mixedexternal audio signals are received at a first one of the localconnection ports from a second conferencing device, and the local mixedmicrophone signal and the local mixed external audio signal are providedto a second one of the local connection ports for transmission to athird conferencing device.
 8. The method of claim 7, further comprising:providing the one or more auxiliary mixed microphone signals and the oneor more auxiliary mixed external audio signals to the second localconnection port for transmission to the third conferencing device. 9.The method of claim 1, wherein determining the gain adjustment value foreach auxiliary mixed microphone signal includes: identifying a firstauxiliary mixed microphone signal as being received from a secondconferencing device positioned adjacent to the first conferencing devicewithin the daisy-chain configuration; and selecting a first gainadjustment value that decreases a strength of the first auxiliary mixedmicrophone signal based on the identified position of the secondconferencing device.
 10. The method of claim 9, wherein determining thegain adjustment value for each auxiliary mixed microphone signal furtherincludes: identifying a second auxiliary mixed microphone signal asbeing received from a third conferencing device positioned non-adjacentto the first conferencing device within the daisy-chain configuration;and based on the identified position of the third conferencing device,selecting a second gain adjustment value that adjusts a strength of thesecond auxiliary mixed microphone signal to above that of the firstauxiliary mixed microphone signal.
 11. The method of claim 1, whereinthe gain adjustment value for each auxiliary mixed microphone signal isproportional to a distance between the first conferencing device and thecorresponding other conferencing device.
 12. A conferencing device forcommunicatively coupling to one or more other conferencing devices in adaisy-chain configuration, the conferencing device comprising: a pair oflocal connection ports configured for communicatively connecting to atleast one of the one or more other conferencing devices, at least one ofthe local connection ports being further configured to receive one ormore auxiliary mixed microphone signals from the one or more otherconferencing devices, wherein each auxiliary mixed microphone signalcomprises a mix of microphone signals captured by a respective one ofthe other conferencing devices; one or more processors configured to:determine a gain adjustment value for each auxiliary mixed microphonesignal based on a position of the other conferencing device thatcaptured the signal, relative to a position of the conferencing devicewithin the daisy-chain configuration, adjust a gain value for eachauxiliary mixed microphone signal based on the corresponding gainadjustment value, and generate a loudspeaker signal from the one or moregain-adjusted auxiliary mixed microphone signals; and at least oneloudspeaker for outputting the loudspeaker signal.
 13. The conferencingdevice of claim 12, further comprising a digital audio bus configured tofacilitate communication with the local connection ports.
 14. Theconferencing device of claim 13, wherein the digital audio bus isconfigured to determine the position of the conferencing device withinthe daisy-chain configuration upon identifying one or more connectionsto the one or more other conferencing devices at the local connectionports.
 15. The conferencing device of claim 12, further comprising: oneor more external communication ports configured to connect to one ormore external communication devices and receive one or more localexternal audio signals from the one or more external communicationdevices, wherein the one or more processors are further configured to:generate a local mixed external audio signal from the one or more localexternal audio signals, and provide the local mixed external audiosignal to at least one of the local connection ports.
 16. Theconferencing device of claim 15, wherein at least one of the localconnection ports is further configured to receive one or more auxiliarymixed external audio signals from the one or more other conferencingdevices, each auxiliary mixed external audio signal comprising a mix ofexternal audio signals received by a respective one of the otherconferencing devices; and wherein the one or more processors are furtherconfigured to: generate a global mixed external audio signal from theone or more local external audio signals and the one or more auxiliarymixed external audio signals, and generate the loudspeaker signal bymixing the one or more gain-adjusted auxiliary mixed microphone signalswith the global mixed external audio signal.
 17. The conferencing deviceof claim 16, further comprising: at least one microphone configured toprovide one or more local microphone signals, wherein the one or moreprocessors are further configured to: generate a local mixed microphonesignal from the one or more local microphone signals; provide the localmixed microphone signal to at least one of the local connection ports;and for each of the one or more external communication ports: generate afar-end output signal from the local mixed microphone signal, theauxiliary mixed microphone signal, the auxiliary mixed external audiosignal, and the one or more local external audio signals received fromeach other external communication port, and provide the far-end outputsignal to the respective external communication port.
 18. Theconferencing device of claim 12, wherein the pair of local connectionports includes: a first local connection port connected to a secondconferencing device for receiving the one or more auxiliary mixedmicrophone signals and the one or more auxiliary mixed external audiosignals from the second conferencing device, and a second localconnection port connected to a third conferencing device for providingthe local mixed microphone signal and the local mixed external audiosignal to the third conferencing device.
 19. The conferencing device ofclaim 18, wherein the second local connection port is further forproviding the one or more auxiliary mixed microphone signals and the oneor more auxiliary mixed external audio signals to the third conferencingdevice.
 20. The conferencing device of claim 12, wherein the one or moreprocessors are further configured to determine the gain adjustment valuefor each auxiliary mixed microphone signal by: identifying a firstauxiliary mixed microphone signal as being received from a secondconferencing device positioned adjacent to the conferencing devicewithin the daisy-chain configuration, and selecting a first gainadjustment value that decreases the strength of the first auxiliarymixed microphone signal based on the identified position of the secondconferencing device.
 21. The conferencing device of claim 20, whereinthe one or more processors are further configured to determine the gainadjustment value for each auxiliary mixed microphone signal by:identifying a second auxiliary mixed microphone signal as being receivedfrom a third conferencing device positioned non-adjacent to theconferencing device within the daisy-chain configuration, and based onthe identified position of the third conferencing device, selecting asecond gain adjustment value that adjusts a strength of the secondauxiliary mixed microphone signal to above that of the first auxiliarymixed microphone signal.
 22. The conferencing device of claim 12,wherein the gain adjustment value for each auxiliary mixed microphonesignal is proportional to a distance between the conferencing device andthe corresponding other conferencing device.
 23. A conferencing systemcomprising: a plurality of conferencing devices arranged in adaisy-chain configuration, each conferencing device comprising: a pairof local connection ports configured for communicatively connecting toat least one other conferencing device, one or more externalcommunication ports configured to connect to one or more externalcommunication devices, at least one microphone configured to provide oneor more local microphone signals, at least one loudspeaker foroutputting a loudspeaker signal, and one or more processors forprocessing received audio signals and providing the processed audiosignals to one or more components of the conferencing device; one ormore interconnects configured for coupling to the local connection portsof the plurality of conferencing devices, wherein each of theconferencing devices receives one or more auxiliary mixed microphonesignals at one or more of the local connection ports and provides alocal mixed microphone signal to at least one of the local connectionports, the local mixed microphone signal comprising a mix of microphonesignals captured by its own microphones, and each auxiliary mixedmicrophone signal comprising a mix of microphone signals captured by themicrophones of a respective one of the other conferencing devices; andwherein the one or more processors of each conferencing device isconfigured to: determine a gain adjustment value for each auxiliarymixed microphone signal based on a position of the other conferencingdevice that captured the signal, relative to a position of theconferencing device within the daisy-chain configuration, adjust a gainvalue for each auxiliary mixed microphone signal based on thecorresponding gain adjustment value, and generate the loudspeaker signalfrom the one or more gain-adjusted auxiliary mixed microphone signals.24. The conferencing system of claim 23, wherein each conferencingdevice: receives one or more local external audio signals at the one ormore external communication ports, generates a local mixed externalaudio signal from the one or more local external audio signals, andprovides the local mixed external audio signal, along with the localmixed microphone signal, to the at least one of the local connectionports; and receives one or more auxiliary mixed external audio signals,along with the one or more auxiliary mixed microphone signals, at theone or more of the local connection ports, each auxiliary mixed externalaudio signal comprising a mix of the external audio signals received bya respective one of the other conferencing devices.
 25. The conferencingsystem of claim 24, wherein the one or more processors of eachconferencing device are configured to: generate a global mixed externalaudio signal from the one or more local external audio signals and theone or more auxiliary mixed external audio signals, and generate theloudspeaker signal by mixing the one or more gain-adjusted auxiliarymixed microphone signals with the global mixed external audio signal.26. The conferencing system of claim 23, wherein each conferencingdevice determines its own position within the daisy-chain configurationupon identifying one or more connections to one or more of the otherconferencing devices at the local connection ports of said device. 27.The conferencing system of claim 23, wherein each conferencing devicefurther includes a digital audio bus configured to facilitatecommunication with its local connection ports and determine the positionof said conferencing device within the daisy-chain configuration. 28.The conferencing system of claim 27, wherein each conferencing devicesends its position within the daisy-chain configuration to the otherconferencing device coupled to a first one of the local connectionports.
 29. The conferencing system of claim 28, wherein once a first oneof the plurality of conferencing devices is determined to be in a firstposition within the daisy-chain configuration, each remainingconferencing device sequentially determines its position within thedaisy-chain configuration based on the position information received atthe first local connection port.
 30. The conferencing system of claim29, wherein the first one of the conferencing devices determines itsfirst position within the daisy-chain configuration upon identifying aconnection to one of the other conferencing devices at a second one ofthe local connection ports and the absence of a connection at the firstlocal connection port.
 31. The conferencing system of claim 27, whereinone of the conferencing devices is assigned as a master device and theremaining conferencing devices are assigned to be slave nodes on thedigital audio bus, the master device being configured to seriallydiscover the position of each slave node within the daisy-chainconfiguration.
 32. The conferencing system of claim 23, wherein a firstconferencing device determines the gain adjustment value for a first oneof the one or more auxiliary mixed microphone signals by: identifyingthe first auxiliary mixed microphone signal as being received from asecond conferencing device positioned adjacent to the first conferencingdevice within the daisy-chain configuration; and selecting a first gainadjustment value that decreases the strength of the first auxiliarymixed microphone signal based on the identified position of the secondconferencing device.
 33. The conferencing system of claim 32, whereinthe first conferencing device determines the gain adjustment value for asecond one of the one or more auxiliary mixed microphone signals by:identifying the second auxiliary mixed microphone signal as beingreceived from a third conferencing device positioned non-adjacent tosaid conferencing device within the daisy-chain configuration; and basedon the identified position of the third conferencing device, selecting asecond gain adjustment value that adjusts a strength of the secondauxiliary mixed microphone signal to above that of the first auxiliarymixed microphone signal.
 34. The conferencing system of claim 33,wherein the second conferencing device is positioned between the firstconferencing device and the third conferencing device within thedaisy-chain configuration.